1. Field of the Invention
This invention relates to computer systems and, more particularly, to protection of data objects of a primary computing device at one or more other devices including a peripheral memory device.
2. Description of the Related Art
The computing infrastructure of a modern enterprise may include thousands of computing devices, which may range in complexity from clustered multiprocessor servers at the high end to relatively simple hand-held devices at the low end. At any given point in time, a large number of the computing devices may hold data objects containing information such as sales presentations, project plans, product designs, source code, and so on, that may be critical to the success of one or more organizational units. A number of different types of data protection techniques have traditionally been implemented in order to enable recovery of the data objects from various types of failure situations, such as a system crash, sustained loss of electrical power, an attack by malicious software such as a virus, or a natural disaster such as a hurricane, tornado, flood or fire. For example, automated backups to secondary storage may be scheduled at regular intervals (e.g., once every day) from servers, desktops and laptops that are connected to a corporate network, and periodic replication of mission-critical portions of the data to geographically remote locations may be organized for disaster recovery.
Traditional automated backup operations often require the primary system (e.g., a laptop or desktop computer whose data objects are to be backed up) to be connected to a network (e.g., a corporate intranet) during backup: for example, the secondary backup device to which the data is backed up may be linked to the primary system via a network, and/or at least part of the software responsible for performing the backup may be executed at a backup manager that is linked to the primary system via a network. During time windows when a primary system (such as a laptop being used for a business trip) does not have connectivity to the network on which its automated backups are usually performed, the data stored at the primary system may be vulnerable to failures. Of course, the user of the primary system may manually initiate the creation of a backup copy of an important data object while the primary is disconnected from the network, e.g., to a writeable compact disc (CD) or writable digital video disc (DVD) device attached to the primary system. However, manual backup procedures that depend on users to remember to identify the data objects that should be protected, and on the users' technical ability to correctly create and safeguard backup versions of the identified data objects, cannot generally be relied upon by corporate information technology (IT) organizations.
In addition to the problem of time windows during which network-based backups may not be feasible, traditional backup techniques may also suffer from additional deficiencies. For example, in performing a task such as preparing a presentation for a customer briefing, a user of a primary system may utilize a set of documents or files. The user may update some of the documents of the set, and perform only read operations to reference other documents of the set. From the point of view of the user, in the event of a failure such as a disk crash, it may be important to be able to quickly recover all the documents of the set, including the ones that were referenced but not updated. Unfortunately, traditional backup techniques are often oriented largely towards protecting data affected by update operations: e.g., when a backup is performed, only the changes made to one or more data objects since the previous backup may be saved in some backup techniques. As a result, quickly recovering the entire set of documents needed for the user's task, including documents that have only been read (but not necessarily written) in the recent past, may be difficult using some traditional backup techniques.